Certain characteristics of the more economical forms of electrical light socket make the sockets incompatible with high wattage light bulbs. Other characteristics complicate the process of connecting power wiring with the socket during installation. The switching or power control components of the prior light sockets have been restricted to certain specific types and do not provide for a desirably broad range of different modes of control.
The limitation on the wattage of the bulbs which are used with such sockets is caused by the heat which is produced by light bulbs. Sockets of the above discussed kind have contacts, conductors and insulative materials that have a low tolerance for heat. Consequently, such sockets have been considered to be unsuitable for use with high wattage light bulbs which generate relatively large quantities of heat. Sockets of the more common kinds are typically limited to use with bulbs operating at 150 watts or less. The wattage limit drops to about 100 watts if the installation requires that the bulb and socket be inverted.
Problems arising from the need to avoid heat damage are aggravated in the case of light sockets which include electronic circuit components for the purpose of controlling a lamp or light fixture. Typically, such components may have a maximum temperature tolerance of about 80.degree. C. Such components produce heat when conducting current and this must be dissipated in order to avoid a damaging temperature build-up. Conventional heat sink arrangements for solid state circuit components may be inadequate in this context, particularly if a high wattage bulb is engaged in the socket and is also producing heat.
Thus an economical light socket construction which more effectively dissipates heat would be highly advantageous.
Installation of some forms of light socket requires connection of a lamp cord or other power conductor to terminals of the socket. The power terminals should be inside the socket or be enclosed in some other manner for safety reasons. Access to the power terminals for the purpose of making or repairing such connections is undesirably difficult in prior light sockets. Arrangements for preventing accidental exposure of power terminals, for preventing misconnection of wires and for preventing short circuits between stranded wires in the vicinity of the power terminals are often less effective than would be desirable.
Sockets often include switching means for turning a lamp or light fixture on or off and in some cases for varying the intensity of the light which is produced by the lamp or fixture. Mechanical switches have in some cases been replaced with electronic switch circuits which respond to touching of the socket or some component of the lamp or fixture which is in electrical contact with the socket. Prior sockets which have such self contained electronic switching means control only the single light bulb which is engaged in the socket. It would be advantageous if the socket could, optionally, be used to control additional bulbs in additional sockets or to respond jointly with additional sockets to touching of a single element.
Prior touch controlled sockets of the above described kind are unsuitable for use at elevated locations that can not be conveniently reached by an operator. This has had the effect of restricting usage of such sockets at locations where they might otherwise be the preferred type of socket.
Prior sockets containing electronic switching means respond only to touch and are incapable of responding to more than one mode of actuation. It would be advantageous to provide such sockets with the capability of responding to two or more types of actuation such as touch, loud noises, changes in daylight, high temperature or intrusion of a person into a room, for example.
The present invention is directed to overcoming one or more of the problems discussed above.